Contact jaw for a blade contact



March 19, 1963 w. BRANDHORST CONTACT JAW FOR A BLADE CONTACT Filed March 25. 1960 INV EN TOR BY ddfim %4r% 9'- We ATTORNEYS United States Patent 3,082,399 CONTACT JAW FUR A BLADE CONTACT Willem Brandhorst, Hengelo, Netherlands, assignor to N.V. Fabriek Van Eiectrische Apparaten Voorheen F.

Hazemeijer & (20., Hengelo, a corporation of the Netherlands Filed Mar. 25, 1960, Ser. No. 17,657 Claims priority, application Netherlands Mar. 26, 1959 2 Claims. (Cl. 339-259) The invention relates to a contact jaw for a blade con tact, comprising two springs-loaded, nearly parallel contact plates which extend into two extensions with a gradually increasing distance and which merge 1nto a basepart that is nearly perpendicular to the contact plates.

Such a contact jaw is known from the German patent specification No. 953,717. In this known embodiment the spring pressure is provided by thin C-shaped springs. This has, however, the disadvantage that these springs, apart from being quite costly, cannot provide a great pressure, so that the necessary contact pressure must be provided bythe elasticity of the material of the contact jaws and their extensions, which therefore must be unnecessarily heavy.

The invention aims to do away with these disadvantages and to this end the spring pressure is supplied by one or more twisted plate springs, the torsion of which furnishes the spring pressure. These springs are positioned in the space between the extensions and the base plate. Further there are provided two or more pressure members, coupled to the respective contact plates and positioned nearly perpendicular to these plates, while each one of these members is provided with a slot through which the plates springs run.

The advantage of this construction lies in the fact that it is now possible to use cheap plate springs, while it is further possible to obtain a very high contact pressure.

It is advantageous to make use of three flat C-shaped pressure members, one cross-leg of each pressure member being provided with a slot, perpendicular through which the springs run, while the extensions of the contact plates are provided with longitudinal slots, namely in the one plate near the edges and in the other plate near the centre, each of these slots guiding a pressure member which rests with the one, not slotted cross-leg against the plate while the other leg extends into the space between the extensions and the base plate, the plate springs running through the aligned slots while the ends of the springs are twisted with regard to the centre through a certain angle that depends upon the desired spring pressure.

It is further advantageous when both the short edges of the springs are provided with a small extension that is parallel to these edges.

The figures show an embodiment according to the invention. It is observed, however, that the invention is not limited to this embodiment.

FIGURE 1 shows the use of the novel contact jaw in a fuse-base while the FIGURES 2 and 3 show the mutual position of the pressure members.

As is clear from FIGURE 1 the contact jaw comprises two parallel contact plates 1 with extensions 2 which merge into the base plate 3. These three parts are, together with the terminal strips 4, made in one piece. The extensions 2 are provided with longitudinal slots 5 and 6, the slots 5 lying near the edges ofone extension while the slot 6 lies approximately at the centre of the opposite extension. These slots guide the pressure me m bers 7, each one of which, as is also shown in FIGURES 2 and 3, comprises a slot 8. Two plate springs 9 are thrust through the slots 8 in the pressure members 7. The contact plates may be pressed together before the springs are brought into place while it is also possible to make use of a hole, made in one of the contact plates, as is the case with the left contact jaw in FIGURE 1. he head of the middle pressure member 7 fits into this hole and when the springs 9 are brought into place the pressure member is again brought at a certain distance from the pressure plate by the use of a detend part, for instance a small cap 10, that fits partly into the hole in the contact plate. In both cases the plate springs are twisted and the torsion supplies the spring pressure that is necessary to obtain the contact pressure between the contact plates 1 and the blade contacts 11 of the fuse 12. Both complete jaws contacts are mounted on the sulating parts 13, these being fixed to the base 14.

FIGURE 2 shows a perspective view of the pressure members 7 with the springs. It is clear that, when the distance between the heads 7 of the pressure members increases the ends of the springs 7 will be twisted with respect to the centre of the spring.

FIGURE 3 shows a side view of the pressure members; this figure needs no further explanation.

The slot 8 has a particular shape; it consists namely of two parallel parts, which are shifted with respect to each other. This particular shape makes it easy to bring the springs 9 into place. By forming the short outer edges of the springs 9 with a small extension the spring is prevented from moving out of the slot.

What I claim is:

1. A contact jaw for a blade contact comprising two spring-loaded substantially parallel contact plates which extend into two extensions with a gradually increasing distance and which merge into a base plate substantially perpendicular to the contact plates, at least one twisted blade spring positioned in the space between the extensions and the base plate, and two or more pressure members coupled to the respective contact plates and positio ned substantially perpendicular to said plates, each of said pressure members being provided with a slot accommodating the blade spring so as to bias the pressure members toward the contact plates.

2. A device according to claim 1 having three flat C-shaped pressure members having a back portion and two terminal cross-leg portions, one cross-leg of each pressure member being one of these slots guiding a pressure member which rests with one cross-leg against the contact plate while the other cross-leg extends into the space between the extensions and the base plate, the spring running through the aligned slots in the pressure members, while the ends of the spring are twisted with respect to the centre through a certain angle that depends upon the desired spring pressure.

References Cited in the file of this patent UNITED STATES PATENTS 753,381

July 29, 1957 

1. A CONTACT JAW FOR A BLADE CONTACT COMPRISNG TWO SPRING-LOADED SUBSTANTIALLY PARALLEL CONTACT PLATES WHICH EXTEND INTO TWO EXTENSIONS WITH A GRADUALLY INCREASING DISTANCE AND WHICH MERGE INTO A BASE PLATE SUBSTANTIALLY PERPENDICULAR TO THE CONTACT PLATES, AT LEAST ONE TWISTED BLADE SPRING POSITIONED IN THE SPACE BETWEEN THE EXTENSIONS AND THE BASE PLATE, AND TWO OR MORE PRESSURE MEMBERS COUPLED TO THE RESPECTIVE CONTACT PLATES AND POSITIONED SUBSTANTIALLY PERPENDICULAR TO SAID PLATES, EACH OF SAID PRESSURE MEMBERS BEING PROVIDED WITH A SLOT ACCOM- 